Operation & Service Manual
Section I
Model 1805B RF Control Unit
Introduction and General Description
ABBREVIATIONS AND ACRONYMS
The following list contains all abbreviations used throughout this manual. Abbreviations and
acronyms that are not listed conform with MIL-STD-12D.
DUT
Device Under Test
ESDS Electrostatic Discharge Sensitive
SAFETY CONSIDERATIONS
The RF Control Unit and all related documentation must be reviewed for familiarization with
safety markings and procedures before performing any operation and/or service. Refer to the
SAFETY SUMMARY located at the beginning of this manual for a summary of safety
information and procedures. Following these simple safety precautions will ensure safe
operation and service of the RF Control Unit.
GENERAL DESCRIPTION
DESCRIPTION OF EQUIPMENT
The following paragraphs provide a general description of the RF Control Unit (shown in
Figure 1-1).
Functional Description
The Model 1805B RF Control Unit is a solid state, microprocessor-controlled RF control unit
designed for precise control ofdc substituted power. When used with thermistor mounts such
as the TEGAM Model 1109,1109H, 1116,1117A, 1119 and 1119H Feedthrough Thermistor
Mounts and a stable RF generator, a system is obtained which allows rapid and accurate
calibration of power meter/sensors and other thermistor mounts from 100 KHz to 26.5 GHz.
Model 1805B also provides:
• IEEE-488 Bus or front panel selection of precise dc power levels. These levels are 0.5
mW and 1-10 mW in 1 mW steps.
• IEEE-488 Bus or front panel RF ON/OFF switching.
• Elimination ofac/dc error by using dc for both bias and substituted power.
• Automatic control of dc level to within ±0.1% +1 mW.
• Constant dc level over an ambient temperature range of from +10° to +40°C.
• Capability to correct RF source level variations of ±3 dB.
• Internal temperature controller for controlling internal temperature of thermistor mount.
Physical Description
Refer to Table 1 -1 for all the physical dimensions for the RF Control Unit, Model 1805B. The
RF Control Unit features a POWER ON/OFF/STANDBY switch/indicators, a
TEMPERATURE control meter, a RF ON/OFF switch/indicator, DC SUBSTITUTED
POWER (mW) control, BRIDGE BALANCE meter, MOUNT BIAS connectors,
REMOTE/LISTEN/ERROR indicators, and FINE/COARSE NULL ADJUST controls, which
are all located on the front panel. The rear panel contains the input power connector and fuse
selector assembly, INPUT/OUTPUT REMOTE PROGRAM connectors, ADDRESS selector
switch, IEEE 488 INTERFACE BUS connector, and+/- AM MODULATION connectors. The
RF Control Unit can be easily stacked with other TEGAM instruments or mounted in any
cabinet or rack designed according to EIA RS-310 and M1L-STD-189 using the appropriate
hardware. Figure 1-2 and the following list are provided as an aid in identifying and locating
modules and assemblies within the Models 1805B RF Control Unit.
A1 MICROPROCESSOR PC BD ASSEMBLY
A2 DC SUBSTITUTION PC BD ASSEMBLY
A3 RF POWER BD ASSEMBLY
A4 (NOT USED)
A5 (NOT USED)
A6 POWER SUPPLY/MOTHER BD ASSEMBLY
1-3
